CCEA Glossary of Terms Flashcards
atomic number
the number of protons in the nucleus of an atom
mass number
total number of protons and neutrons in (the nucleus of an atom.
Isotopes
atoms which have the same number of protons (so they are atoms of the same element) but they have a different number of neutrons (so they have a different mass number).
Cation
positive ion
Anion
negative ion.
compound
substance formed when two or more elements are chemically combined.
ionic bond
attraction between oppositely charged ions.
covalent bond
formed by a shared pair of electrons.
Diatomic
two atoms covalently bonded in a molecule.
Metallic bonding
attraction between delocalised electrons and the positive ions in a regular lattice.
Malleable
can be hammered into shape.
Ductile
drawn out into wires.
alloy
mixture of two or more elements at least one of which is a metal and the resulting mixture has metallic properties.
nanometre
10-9m
nanoparticle
A structure that is 1 - 100 nm in size.
Allotropes
are different forms of the same element in the same physical state.
element
substance that consists of only one type of atom and it cannot be broken down into anything simpler by chemical means.
compound
substance that consists of two or more elements chemically combined.
atom
the simplest particle of an element that can exist on its own in a stable
environment.
molecule
a particle that consists of two or more atoms chemically bonded together.
period
A horizontal row in the Periodic Table.
group
vertical column in the Periodic Table.
relative atomic mass
the mass of the atom compared with that of the carbon 12 isotope, which has a mass of exactly 12, and it is the weighted mean ofthe mass numbers
Percentage yield
Actual yield
theoretical yield x 100
Water of crystallisation
water that is chemically bonded into the crystal structure.
Hydrated
solid crystals contain water of crystallisation.
Dehydration
removal of water of crystallisation.
anhydrous
substance does not contain water of crystallisation.
degree of hydration
the number of moles of water of crystallisation chemically bonded in 1 mole of the compound.
empirical formula
The simplest whole number ratio of the atoms of each element in a compound.
molecular formula
the actual number of atoms of each element in a molecule.
An indicator
a chemical that gives a colour change in acidic, alkaline and neutral solutions.
A base
a substance that reacts with an acid producing a salt and water.
Alkali
a soluble base.
strong acid
ionises completely in water.
Ionises
Breaks down
weak acid
ionises partially in water.
strong alkali
ionises completely in water.
weak alkali
ionises partially in water.
Neutralisation
the reaction between an acid and an alkali producing a salt and water.
A salt
a compound formed when some or all of the hydrogen ions in an acid are replaced by metal ions or ammonium ions.
pure substance
a single element or compounds (and is not mixed with any other substance).
mixture
defined as two or more substances mixed together, which are usually easy to separate.
melting point
(or melting temperature) is the temperature at which a solid changes
into a liquid.
boiling point (boiling temp)
is the temperature at which a liquid changes into a gas
formulation
a mixture which has been designed as a useful product and has been designed as a useful product and is formed by mixing together several different substances in carefully measured quantitites to ensure the product has the required properties
soluble substance
soluble substance dissolves in water.
insoluble substance
insoluble substance does not dissolve in water.
solute.
soluble substance which dissolves
Solvent
The liquid in which the solute dissolves is the solvent.
Solution
mixture of solute dissolved in a solvent is a solution.
Miscible
Miscible liguids mix.
Immiscible
Immiscible liquids do not mix.
The filtrate
The filtrate is the filtered solution.
The residue
The residue is the solid which remains on the filter paper.
Rf
Distance moved by spot
Distance moved by solvent
saturated solution
saturated solution is one in which no more solid will dissolve in water at a particular temperature.
Precipitate
a solid which may be formed on mixing two solutions.
Solubility
the mass of solid that will saturate 100 g of water (or solvent) at a particular
temperature.
displacement reaction
a reaction in which a more reactive metal takes the place of a less reactive metal in a compound.
redox reaction
Reaction in which oxidation and reduction occur at the same time.
Oxidation
gain of oxygen, loss of hydrogen or loss of electrons.
Reduction
loss of oxygen, gain of hydrogen or gain of electrons.
Rust
hydrated iron(III) oxide.
activation energy
the minimum energy required for a reaction to occur.
catalyst
a substance that increases the rate of a chemical reaction without being used up.
reversible reaction
reaction where reactants can change into products and the products can change back into the reactants.
dynamic equilibrium
occurs when the rate of the forward reaction is equal to the rate of the reverse reaction resulting in the amount of reactants and products remaining constant.
equilibrium reaction
considered to be a closed system where only the reactants and products are present.
homogeneous reaction (or system)
Reaction or system in which all the reactants and products are in the same state.
Endothermic reaction
Takes in heat
Titration
Reacting two solutions together to determine the No of moles of the solute in one of the solutions
Avogrados Law
Equal vols of gases under same conditions of temp and pressure contain same No of particles
Exothermic reaction
Gives out heat
Combustion
Reaction fuel + O2 = oxides + heat released
